BEIRUT, Lebanon — Government and opposition supporters clashed at a Beirut university campus Thursday, battering each other with sticks, stones and even pieces of furniture in new violence spilling over from Lebanon’s political crisis. Four people were killed, security sources told Reuters.

Two opposition students and two other people were shot dead and 100 were injured, many by gunfire, at Beirut's Arab University, the sources said.

Other news outlets reported at least two deaths and up to 35 people wounded in the clashes. NBN, an opposition-run television station, said two of the dead were students loyal to the opposition, which includes the Shiite Muslim Hezbollah and Amal groups.

Black smoke poured into the sky from cars engulfed in flames as armored vehicles full of troops moved in to try to keep the two sides apart. But the riot spread into the nearby streets around Beirut Arab University as students smashed parked cars and battled for hours.

The battle grew out out of a argument between pro-government Sunni Muslims and supporters of the Shiite Hezbollah opposition movement in the university cafeteria, students said.

As the melee grew, Hezbollah supporters called in help, and residents from the surrounding Sunni neighborhood joined in. Dozens of vigilantes wearing blue and red construction hats and carrying makeshift weapons — chair legs, pipes, garden tools, sticks and chains — converged on the university and started clashing with the police.

The army was called in with armored vehicles and fired tear gas and live fire in the air to disperse the crowd.

Earlier, Hezbollah’s al-Manar TV reported one of the Shiite group’s supporters was killed. Security officials could not confirm the death.

Tense timesThe growing street battle illustrated Lebanon's struggle to contain violence sparked by the power struggle between the Hezbollah-led opposition and the U.S.-backed government of Prime Minister Fuad Saniora. Many fear the violence could spiral out of control and even plunge the country into a new civil war.

The university melee came two days after a general strike called by the opposition turned into the worst day of violence since the political crisis began. The strike sparked opposition-government clashes around the country that killed three people and took on a dangerous sectarian tone, with fights between Sunni Muslims and Shiites.

Saniora on Thursday was in Paris at a conference of donor nations that promised more than $7 billion in aid to rebuild after this summer’s devastating Hezbollah-Israel war. The money aims to boost Saniora’s government, but the chaos at home has raised doubts whether his government can properly use the money.

The trouble at the university, located in the mainly Sunni Muslim neighborhood of Tarik el-Jadideh, began when an argument broke out in the university cafeteria between pro-government Sunni students and Hezbollah and other anti-government supporters. They said university security broke up the fight, but the Sunni supporters encircled the campus.

Amid the brawl, some students claimed they came under fire from snipers nearby. Mohammed Abdul-Sater, a 21-year-old Shiite student, said he saw at least three people wounded by the gunfire.

“We are afraid about the future of the country,” he said. “We are afraid about civil war,” said Abdul-Sater.

Calls for restraintAs the battle spilled into the streets, people from outside the university joined in. Young men carrying sticks and wearing hard hats came in and pelted each other with stones. Some flung pieces of furniture. Soldiers fired volleys of automatic rifle fire into the air, and residents of the area fled for cover.

Seeking to prevent the trouble from spreading, Hezbollah’s leadership issued a statement on al-Manar accusing pro-government factions of provoking the clashes and calling on its supporters to get off the streets to “avoid strife being inflamed” by government supporters.

Saad Hariri, leader of the parliamentary majority and the leading Sunni opponent of Hezbollah, also urged his supporters to exercise restraint.

The opposition has staged two months of demonstrations and sit-ins in a bid to topple Saniora’s government. The prime minister has refused the opposition’s demand for veto-wielding share of the Cabinet.

Lebanon fought a 15-year civil war between its Christian and Muslim communities, ending in 1990. The current political crisis has divided the country along different lines, with Sunnis largely backing Saniora, Shiites behind Hezbollah, and Christians divided between the two camps.